70 lines
1.2 KiB
C
70 lines
1.2 KiB
C
#include <blue/core/bitop.h>
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#include <intrin.h>
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#include <assert.h>
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#define CPU_FEATURE_YES 1
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#define CPU_FEATURE_NO -1
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#define CPU_FEATURE_UNKNOWN 0
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static int cpu_supports_popcnt = CPU_FEATURE_UNKNOWN;
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static int check_popcnt_support()
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{
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int d[4];
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__cpuid(d, 0x00000001);
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return (d[2] & 0x800000) ? CPU_FEATURE_YES : CPU_FEATURE_NO;
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}
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int b_popcountl(long v)
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{
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if (cpu_supports_popcnt == CPU_FEATURE_UNKNOWN) {
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cpu_supports_popcnt = check_popcnt_support();
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}
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if (cpu_supports_popcnt == CPU_FEATURE_YES) {
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#if _M_AMD64 == 100
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return __popcnt64(v);
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#else
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return __popcnt(v);
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#endif
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}
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assert(0 && "CPU does not support popcount!");
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return 0;
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}
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int b_ctzl(long v)
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{
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unsigned long trailing_zero = 0;
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#if _M_AMD64 == 100
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int x = _BitScanForward64(&trailing_zero, v);
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#else
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int x = _BitScanForward(&trailing_zero, v);
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#endif
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if (x) {
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return trailing_zero;
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} else {
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return 64;
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}
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}
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int b_clzl(long v)
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{
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unsigned long leading_zero = 0;
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#if _M_AMD64 == 100
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int x = _BitScanReverse64(&leading_zero, v);
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#else
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int x = _BitScanReverse(&leading_zero, v);
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#endif
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if (x) {
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return 64 - leading_zero;
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} else {
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// Same remarks as above
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return 64;
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}
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} |